Feeding sheets of media along a path is necessary in printers, copiers and so on. A wide range of feed assemblies have been developed for sequentially conveying sheets along a feed path with the required degree of positional accuracy for each conveyed sheet. This is particularly true of media feed assemblies in printers. The position of the print media substrate and the printhead must be closely controlled.
The need for accurate media feed is generally counter to a compact overall design of the printer. Several sets of pinch rollers along the media feed path can ensure that the media sheet is gripped firmly and driven without any slippage. However, the space required for multiple pinch roller sets and their respective drives adds to the bulk of the printer. This is particularly problematic for portable or handheld printers, especially if the printer is incorporated as an additional component of a camera, mobile phone, PDA or similar handheld electronic device.
It is possible to accurately feed media past a printhead using a single set of pinch rollers. However, the single roller set needs to hold the media without slippage and drive the media at a constant speed. The entire assembly needed to achieve this can substantial bulk and weight to a hand-held electronic device.